Efficient silicon carbide substrate cutting method based on ultrasonic vibration and steel wire radial clockwise and anticlockwise rotation

Abstract

The invention relates to the technical field of semiconductor material processing, discloses an efficient silicon carbide substrate cutting method based on ultrasonic vibration and steel wire radial clockwise and anticlockwise rotation, and aims to solve the problems that traditional wire cutting is low in efficiency and poor in quality, consumables are short in service life, laser cutting is high in cost, thermal damage is caused and the like. The method is characterized in that high-frequency ultrasonic vibration is axially applied to a cutting steel wire, meanwhile, the steel wire conducts low-frequency reciprocating linear motion, and accurate synchronous cooperative control is conducted on the steel wire; and meanwhile, steel wire self-adaptive tension control and composite abrasive material supply are carried out. By the adoption of the technical scheme, the cutting efficiency of the silicon carbide substrate can be remarkably improved by 150% or above, the service life of the cutting line is prolonged by one time or above, and the high-quality silicon carbide substrate with the surface roughness Ra not higher than 0.2 micrometer and without subsurface damage is obtained.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material processing technology, and more specifically, relates to an efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial forward and reverse rotation of steel wire. Background Technology

[0002] In the current fields of power electronics, radio frequency communication, and optoelectronics, which are centered on third-generation semiconductor materials, silicon carbide (SiC) has become a key substrate material for manufacturing high-performance power devices, radio frequency devices, and high-temperature sensors due to its excellent physical properties such as wide bandgap, high thermal conductivity, high breakdown field strength, and high electron saturation velocity. With the rapid development of downstream industries such as new energy vehicles, 5G communication, and photovoltaic power generation, the demand for large-size, high-quality silicon carbide substrates has exploded. This makes the efficiency, precision, and cost control of cutting technology, the core processing link from ingot to wafer, a key technological bottleneck restricting the development of the entire industry chain. The near-diamond-level hardness (Mohs hardness as high as 9.2) and brittleness of silicon carbide material itself pose extremely stringent challenges to the cutting process. Traditional cutting methods often struggle to balance efficiency, material loss, and processing quality when addressing this challenge, prompting the industry to continuously explore more advanced technological paths.

[0003] Against this backdrop, those skilled in the art have made many beneficial attempts. For example, machining methods represented by wire EDM are widely used due to their technological maturity and cost advantages. Among them, Chinese patent CN111516160B discloses a technical solution that optimizes the groove pitch design of the grooved wheel used for bonded abrasive cutting wires to ensure the uniformity and stability of the wear of the cutting wire during operation. The initial design intention of this solution is to precisely control the position and wear state of the cutting wire within the grooved wheel, so that the entire wire array can maintain highly consistent physical properties during the cutting process, thereby effectively solving the problems of poor substrate thickness consistency and low surface flatness caused by uneven wear of the cutting wire. From a technical contribution perspective, this solution has profoundly understood and solved the core element of "stability" in the wire EDM process, providing important technical support for improving the geometric accuracy and macroscopic surface quality of silicon carbide substrates. However, with the continuous development of related technologies and the increasingly stringent requirements for performance indicators in application scenarios, the inherent characteristics of the above-mentioned technical solution, which focuses on optimizing unidirectional motion stability, have gradually revealed their limitations in addressing new challenges. The reason for this lies in the fact that this type of technology essentially still relies on the unidirectional high-speed translational motion of a steel wire to remove material. In this single motion mode, the cutting behavior at the microscopic level manifests as the "scraping" effect of abrasive grains on silicon carbide material. Each abrasive grain on the steel wire contacts the workpiece with a relatively fixed cutting edge, which not only leads to low utilization of the abrasive grains and severe tip wear, but also creates a periodic action pattern in cutting mechanics. This periodic action directly leads to an inherent bottleneck in cutting efficiency. While simply increasing the linear speed or tension can improve the removal rate to some extent, it drastically exacerbates the wear and breakage risk of the steel wire and may form unidirectional and difficult-to-eliminate microscopic scratches on the substrate surface, adversely affecting subsequent epitaxial growth processes. This reveals a deep-seated technical contradiction: the unidirectional motion mechanism adopted to pursue macroscopic stability and surface quality precisely limits the efficiency of material removal at the microscopic level and solidifies a processing mode prone to directional damage, creating an irreconcilable constraint between cutting efficiency, surface quality, and consumable lifespan.

[0004] As another technological approach, non-contact processing methods, represented by lasers, have also been developed. For example, Chinese Patent CN112620973B discloses a stepped laser cutting method that uses a high-energy laser beam to cut single-crystal silicon carbide ingots in layers and steps, demonstrating high cutting efficiency and low physical damage rate. However, this technological path also faces challenges. The equipment investment and maintenance costs of high-power laser systems are relatively high, and the local high temperature and thermal stress generated during the interaction between the laser and matter may create potential hot-dip lattice damage zones (HAZs) in the silicon carbide material, thereby affecting the electrical properties and mechanical strength of the substrate. This is something that must be avoided as much as possible for demanding semiconductor devices.

[0005] In summary, existing silicon carbide cutting technologies, whether mechanical scraping-based wire cutting or thermal ablation-based laser cutting, all face a challenge in balancing efficiency, quality, cost, and material damage. Particularly for mainstream wire cutting technology, the inherent contradiction between efficiency, quality, and material loss in its unidirectional motion principle has become a fundamental obstacle to further performance breakthroughs. Therefore, how to construct a new cutting paradigm that can fundamentally reshape the material removal mechanism at the cutting interface without sacrificing or even improving surface quality and material integrity, by introducing composite motion and high-frequency energy assistance, thereby overcoming the inherent bottlenecks in efficiency and material loss of existing unidirectional wire cutting technology, has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a highly efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise and counterclockwise motion of a steel wire. This method aims to resolve the inherent contradiction between cutting efficiency, processing quality, and consumable lifespan in traditional unidirectional wire cutting technology, as described in the background section, as well as the high cost and thermal damage issues faced by laser cutting technology. This invention fundamentally reshapes the removal mechanism of hard and brittle silicon carbide materials by constructing a composite interaction mode of a high-frequency ultrasonic vibration energy field and a low-frequency reciprocating mechanical field of a steel wire. It aims to significantly improve cutting efficiency and extend the effective lifespan of the cutting wire without sacrificing or even improving substrate surface quality and material integrity, thus providing a novel technical solution for large-scale, low-cost, and high-quality silicon carbide substrate manufacturing.

[0007] To achieve the aforementioned objectives, this invention provides a highly efficient silicon carbide substrate cutting method based on ultrasonic vibration and radial clockwise / counterclockwise motion of a steel wire. The core of this method lies in the precise synchronization and coordinated control of high-frequency, low-amplitude ultrasonic vibration applied along the axial direction of the cutting steel wire and low-frequency, long-range reciprocating linear motion applied along the wire's path. This composite motion mode acts on abrasive particles solidified on the steel wire surface and those floating in the cutting fluid, transforming the action of a single abrasive particle on the silicon carbide workpiece from traditional unidirectional scraping to a composite removal mode combining high-frequency impact chiseling and bidirectional sweeping grinding. The method is implemented using a dedicated cutting device, and its specific execution process includes a series of interrelated technical steps. First, before the cutting operation begins, the entire system is initialized, including precisely fixing the silicon carbide ingot to be cut onto the worktable using a dedicated clamp, and passing a line array composed of multiple cutting steel wires through a guide wheel system to establish a preset wire spacing and initial tension. Subsequently, the cutting process is initiated. The core of this process comprises several parallel and collaborative sub-processes: First, the ultrasonic vibration application assembly is activated, causing the piezoelectric transducer to generate mechanical vibrations of a specific frequency and amplitude. This vibrational energy is then stably and efficiently transmitted to each cutting steel wire via an acoustic amplitude transformer and vibration transmission structure, resulting in high-frequency longitudinal vibration along the steel wire's axis. Second, the reciprocating motion and tension-coordinated control system for the steel wires is activated. This system controls the master and slave servo motors to periodically reverse direction according to a preset motion curve, achieving reciprocating linear motion of the cutting steel wires within the linear array plane. The period and linear velocity of this reciprocating motion are set according to material properties and cutting requirements. Third, adaptive tension closed-loop control is initiated. Tension sensors collect tension data of the linear array in real time, and the motion controller adjusts the output torque of the servo motors in real time based on the deviation between this data and the preset tension target. This dynamically compensates for tension fluctuations caused by ultrasonic vibration, reciprocating reversal, and changes in cutting load, maintaining the linear array tension within a constant, narrow range. Fourth, the composite abrasive supply and circulation system is activated, supplying a cutting suspension containing a specific concentration of nanodiamond particles uniformly and continuously to the cutting area through an array of nozzles. This not only supports the cutting of free abrasive particles but also utilizes the cavitation effect induced by ultrasonic vibration in the liquid to generate micro-jets that assist in material removal and efficiently discharge debris from the cutting area. Throughout the entire cutting process, the central processing and monitoring unit continuously monitors the operational status of all the above subsystems and can adaptively adjust motion and vibration parameters based on signals from in-situ monitoring modules such as acoustic emission sensors until the entire ingot cutting operation is completed.

[0008] As a physical carrier for implementing the aforementioned method, the present invention also provides a high-efficiency silicon carbide substrate cutting device. The device is systematically designed to ensure the precise realization and organic coordination of four core functions: ultrasonic vibration, reciprocating motion, tension control, and abrasive supply. The device includes an ultrasonic vibration application assembly, a steel wire reciprocating motion and tension coordinated control system, a composite abrasive supply and circulation system, and a central processing and monitoring unit.

[0009] Specifically, the ultrasonic vibration application assembly functions to provide stable and controllable axial high-frequency vibration for cutting steel wire. This assembly includes a phase-locked loop (PLL) frequency-tracking ultrasonic generator, a stacked Langevin piezoelectric ceramic transducer, a stepped acoustic amplitude transformer, and a vibration transmission structure. The ultrasonic generator integrates a power amplifier circuit and a PLL control circuit, capable of outputting an electrical signal with a power range of 500 watts to 2000 watts and a center frequency adjustable from 20 kHz to 40 kHz. Its PLL circuit automatically tracks the resonant frequency of the transducer-amplifier-steel wire system, ensuring the system always operates at its highest electromechanical conversion efficiency, with a frequency tracking accuracy no worse than ±10 Hz. The stacked Langevin piezoelectric ceramic transducer uses multiple PZT-8 series piezoelectric ceramic rings and metal electrode plates alternately stacked and secured with central prestressed bolts to achieve stable high-power, high-amplitude output. The stepped acoustic amplitude transformer is made of TC4 titanium alloy, which possesses high fatigue strength and excellent acoustic transmission characteristics. One end of the amplitude transformer is pre-tightly connected to the transducer output surface via a high-strength M12x1.5 thread, while the other end is designed with a specific cross-sectional size according to the required amplitude amplification factor. Its output end face is connected to the vibration transmission structure. Specifically, the vibration transmission structure consists of a set of vibration transducers corresponding one-to-one with the cutting wire array. These transducers are made of cemented carbide YG8, with a guide groove on their upper surface matching the diameter of the cutting steel wire, and their lower surface rigidly fixed to the output end face of the amplitude transformer. The cutting steel wire passes through this guide groove, thereby applying the longitudinal vibration energy of the amplitude transformer to the steel wire through contact conduction. This structure amplifies the micron-level vibration generated by the transducer to an axial vibration of 5 to 15 microns acting on the steel wire.

[0010] Furthermore, the reciprocating motion and tension coordinated control system for the steel wire is a key component for realizing the core motion mode of this invention and ensuring process stability. The system's hardware includes a pay-off servo motor and a take-up servo motor located at both ends of the wire array, a guide roller assembly consisting of an active drive roller and multiple passive guide rollers, and a three-roller dynamic tension sensor integrated into the fixed guide roller bearing housing. The servo motors are high-response AC permanent magnet synchronous servo motors with encoder resolution of at least 24 bits to ensure precise control of speed and position. The surfaces of the guide roller assembly are all provided with V-shaped guide grooves, and the bottom surface of the grooves is coated with a 0.5 mm thick alumina ceramic coating using plasma spraying technology to improve wear resistance and protect the cutting wire. The three-roller dynamic tension sensor accurately calculates real-time tension by measuring the minute displacement caused by the steel wire pressing against the central roller, and its output signal is an analog voltage signal from 0 to 10 volts. The control core of the system is a dedicated motion controller based on a field-programmable gate array (FPGA). The controller incorporates a feedforward-feedback composite tension control algorithm. The feedback control section is a high-speed PID controller that receives signals from the tension sensor at a sampling frequency of 1 kHz and compares them with the tension setpoint (e.g., set to 30 Newtons) stored in the controller register. Based on the deviation, it calculates and adjusts the differential torque output of the take-up and release servo motors in real time to compensate for steady-state tension drift during the cutting process. The feedforward control section is based on a pre-calibrated system dynamics model. When the controller executes the reciprocating motion reversal command, the feedforward module calculates the overshoot torque necessary to overcome the linear array inertia based on a preset acceleration curve and pre-adds this torque signal to the servo driver command. This feedforward compensation mechanism can proactively intervene before the tension fluctuates significantly due to inertia, thereby controlling the tension overshoot at the moment of reversal within ±5% of the setpoint, ensuring high stability of the cutting process in low-frequency reciprocating motion mode. The cutting steel wire is specifically selected from carbon tool steel wire with a diameter of 0.12 mm. Its core tensile strength is not less than 2800 MPa, and its surface is uniformly coated with a layer of single crystal diamond abrasive grains with an average particle size of 6 micrometers through an electroplating and bonding process. The cutting edge height of the abrasive grains is controlled at 2 to 3 micrometers.

[0011] As another important component of this invention, the composite abrasive supply and circulation system aims to provide a stable supply of free abrasive, enhance cooling and lubrication effects, and achieve the recycling of the cutting fluid. The system includes a storage tank with a stirrer and temperature control module, a high-precision peristaltic pump, an array of nozzles, and a multi-stage filtration and recovery device. The storage tank has a volume of 100 liters and is equipped with a low-speed stirring paddle to prevent the sedimentation of nanodiamond particles. It also integrates a semiconductor cooling (TEC) temperature control module and a temperature sensor, using closed-loop control to maintain the temperature of the cutting suspension at 25 degrees Celsius ± 1 degree Celsius to stabilize its viscosity and fluidity. The cutting suspension is formulated with deionized water, 8% by mass of nano-diamond powder (average particle size 50 nanometers), ethylene glycol antifreeze, and nonionic surfactant. The high-precision peristaltic pump, driven by a stepper motor, provides a precisely adjustable and pulsation-free liquid delivery within the range of 1 liter / minute to 10 liters / minute. The array nozzles, made of wear-resistant silicon nitride ceramic, have an outlet orifice diameter of 0.8 mm. They are installed close to the area where the cutting wire enters the silicon carbide ingot, ensuring that fresh cutting fluid fully wets the entire array. The multi-stage filtration and recovery device, located below the workpiece, consists of a settling tank, a magnetic separator, and a centrifugal solid-liquid separator. It effectively removes silicon carbide powder and detached abrasive particles from the used cutting fluid. The purified liquid is then returned to the storage tank, achieving resource conservation and environmental protection.

[0012] Finally, the central processing and monitoring unit, serving as the command center of the entire device, consists of a Siemens S7-1500 series industrial-grade programmable logic controller (PLC) and a touchscreen human-machine interface (HMI). This unit communicates at high speed with all lower-level execution and control units, such as the ultrasonic generator, FPGA motion controller, and peristaltic pump driver, via a Profinet industrial Ethernet bus. Operators can input and set various process parameters through the HMI interface, such as ultrasonic vibration frequency and amplitude, reciprocating linear velocity (e.g., 1.5 m / s), commutation cycle (e.g., 10 seconds), tension setpoint (e.g., 30 Newtons), and cutting fluid flow rate (e.g., 5 liters / minute). Furthermore, this unit is connected to a broadband acoustic emission sensor mounted on the workpiece fixture. During the cutting process, the PLC analyzes the energy, amplitude, and frequency characteristics of the acoustic emission signal in real time. When an abnormal acoustic emission event caused by the propagation of local hard spots or microcracks is detected, the control system will activate a preset obstacle avoidance program, such as instantly reducing the reciprocating motion speed and ultrasonic vibration amplitude within 0.1 seconds, and restoring the normal settings after the abnormal signal disappears. This enables intelligent monitoring and proactive intervention of the cutting process, further improving the success rate of cutting and the quality of finished products.

[0013] When the cutting method provided by this invention is implemented, its unique material removal mechanism is fully demonstrated. High-frequency axial ultrasonic vibration transforms each diamond abrasive grain fixed to the steel wire into a miniature impact hammer, impacting the silicon carbide material at a frequency of tens of thousands of times per second. This generates extremely high local stress at the contact point, inducing numerous micro-cracks on the material surface and significantly reducing its fracture toughness—a process known as "embrittlement." Simultaneously, the low-frequency linear motion of the steel wire acts as a "sweeping" action. Within half a cycle of its unidirectional motion, the surface material, already "embrittled" by ultrasonic vibration, can be efficiently removed by the abrasive grains on the steel wire with less cutting force. When the direction of motion reverses, the abrasive grains on the other side of the steel wire with lower wear, as well as those in a new cutting posture during the reverse motion, begin cutting the material again. This not only greatly improves the utilization rate of the abrasive grains and the lifespan of the cutting line but also fundamentally eliminates directional scratches generated by unidirectional cutting, improving the microstructure of the processed surface. In addition, the cavitation effect generated by ultrasonic vibration in the cutting fluid creates tiny bubbles that form powerful micro-jet streams and shock waves at the solid-liquid interface. This physical effect enhances the micro-cutting action of the nanodiamond free abrasive particles on the workpiece and also acts as an "acoustic flow cleaning" effect, powerfully flushing away debris from the cutting area, preventing chips from clogging the cutting gap, and ensuring the continuous and efficient cutting process.

[0014] In summary, the efficient silicon carbide substrate cutting method and its dedicated device based on ultrasonic vibration and radial clockwise / counterclockwise motion of steel wire provided by this invention, through the high integration and systematic synergy of multiple technologies such as ultrasonic vibration, reciprocating motion, adaptive tension control, and free abrasive-assisted cutting, constructs a novel mechanical grinding paradigm assisted by a composite energy field. Compared with the traditional unidirectional wire cutting in the prior art, this invention transforms the material removal mechanism from a single "scraping" mode to a composite mode combining "high-frequency impact chiseling" and "bidirectional sweeping grinding," significantly reducing the cutting force and improving the material removal rate at the microscopic level; at the macroscopic level, reciprocating motion and adaptive tension control ensure processing stability and improve the wear state of abrasive particles and steel wire. The final technical effect is that, while obtaining high-quality silicon carbide substrates with a surface roughness Ra value of no more than 0.2 micrometers and no obvious subsurface damage, the cutting efficiency is increased by more than 150% compared with traditional methods, and the replacement cycle of the cutting wire is extended by more than double. This effectively solves the contradiction between efficiency, quality, and cost in the prior art, demonstrating significant technological progress and great industrial application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the high-efficiency silicon carbide substrate cutting device described in this invention.

[0016] Figure 2 This is a system block diagram of the cutting device described in this invention.

[0017] Figure 3 This is a schematic diagram of the ultrasonic vibration application assembly described in this invention.

[0018] Figure 4 This is a schematic diagram of the steel wire reciprocating motion and tension coordinated control system described in this invention.

[0019] Figure 5 This is a schematic flowchart of the cutting method described in this invention.

[0020] The attached figures are labeled as follows: 100, Ultrasonic vibration application assembly; 110, Phase-locked loop frequency automatic tracking ultrasonic generator; 120, Stacked Langevin piezoelectric ceramic transducer; 130, Stepped acoustic amplitude transformer; 140, Vibration transducer; 200, Steel wire reciprocating motion and tension coordinated control system; 210, Wire feeding servo motor; 220, Wire take-up servo motor; 230, Guide wheel assembly; 240, Three-roller dynamic tension sensor; 250, Motion controller; 300, Composite abrasive supply and circulation system; 310, Liquid storage tank; 320, High-precision peristaltic pump; 330, Array nozzle; 340, Multi-stage filtration and recovery device; 400, Central processing and monitoring unit; 410, Industrial-grade programmable logic controller; 420, Touch screen human-machine interface; 430, Acoustic emission sensor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, a detailed description of a high-efficiency silicon carbide substrate cutting method and its dedicated apparatus based on ultrasonic vibration and radial clockwise and counterclockwise rotation of a steel wire, provided by this invention, will be given below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Any equivalent modifications or substitutions made by those skilled in the art under the guidance of this invention should be covered within the scope of protection of this invention.

[0022] Reference Figure 1 and Figure 2Together, they illustrate the overall physical architecture and system control logic of a dedicated device for achieving efficient cutting of silicon carbide substrates according to the present invention. The device, as an organic whole, is constructed on a high-rigidity granite base to ensure extreme stability and vibration reduction performance under the combined effects of high-speed reciprocating motion and high-frequency vibration. The overall layout of the device revolves around the cutting area and mainly includes an ultrasonic vibration application assembly 100 responsible for generating core energy input, a steel wire reciprocating motion and tension coordinated control system 200 for realizing the main motion of material removal, a composite abrasive supply and circulation system 300 providing medium and cooling support for the cutting process, and a central processing and monitoring unit 400 serving as the nerve center of the entire system. These four systems work collaboratively through precise mechanical coupling and high-speed electrical bus communication to jointly execute the unique cutting method proposed in this invention.

[0023] Specifically, the efficient silicon carbide substrate cutting method based on ultrasonic vibration and radial forward and reverse rotation of steel wire proposed in this invention can be fully implemented using this dedicated device. The entire method begins by precisely fixing the silicon carbide ingot to be processed (e.g., a 6H-SiC crystal with a diameter of 150 mm and a length of 30 mm) onto a graphite support block using low-temperature wax or a low-melting-point alloy, and then mounting the support block onto the device's worktable. The worktable has precise micro-motion capability along a direction perpendicular to the linear array plane (i.e., the feed direction). Subsequently, the cutting steel wire (e.g., a linear array consisting of hundreds of parallel steel wires) is passed from the wire feeding side of the wire reciprocating motion and tension coordination control system 200 through the guide roller assembly 230, through the vibration transmission area of ​​the ultrasonic vibration application assembly 100, through the area of ​​the silicon carbide ingot to be cut, and finally around the guide roller assembly 230 at the other end and wound to the take-up side. During this process, the spacing of the linear array is set to determine the final substrate thickness, and an initial reference tension is applied. Once everything is ready, the operator starts the cutting program through the human-machine interface of the central processing and monitoring unit 400, and the device immediately enters an automated cutting cycle. In this cycle, the ultrasonic vibration application assembly 100 imparts axial high-frequency vibration to the linear array, the steel wire reciprocating motion and tension coordination control system 200 drives the linear array to perform low-frequency long-distance reciprocating motion, the composite abrasive supply and circulation system 300 precisely sprays cutting fluid carrying nanodiamond abrasive particles into the cutting area, and the central processing and monitoring unit 400 monitors all status parameters throughout the process and makes adaptive adjustments according to preset logic until the ingot is completely cut into substrates of predetermined thickness.

[0024] The following section will provide a more in-depth and detailed engineering description of the various core subsystems that make up the device.

[0025] First, refer to Figure 3The composition and working principle of the ultrasonic vibration application assembly 100 are described in detail. The core mission of this assembly is to provide stable, uniform, and amplitude-controllable axial high-frequency mechanical vibration for the entire cutting linear array. This begins with a phase-locked loop (PLL) frequency-tracking ultrasonic generator 110, which is essentially a high-performance power signal source. In this embodiment, a digital signal processor (DSP)-controlled intelligent generator is used, capable of outputting a sinusoidal electrical signal with a continuously adjustable center frequency ranging from 19.5 kHz to 40.5 kHz and a rated power of 2000 watts. Its integrated PLL control module can scan the impedance characteristics of the load at a rate of over 1000 times per second, thereby tracking the dynamic resonant frequency of the entire acoustic system (including the transducer, amplitude transformer, vibratory transducer, and cutting linear array) in real time. This automatic tracking capability is crucial because changes in the length, tension, and contact load of the linear array during cutting can cause minute drifts in the system's resonant point. By locking the operating frequency within an extremely narrow bandwidth of ±10 Hz from the resonant point, the generator ensures that the conversion efficiency from electrical energy to mechanical vibration energy is always maintained above 95%, avoiding efficiency loss and system overheating caused by frequency mismatch.

[0026] The high-frequency electrical signal output from the generator is fed into a stacked Langevin-type piezoelectric ceramic transducer 120. This transducer is the core component for realizing electromechanical energy conversion. Its internal structure consists of four pairs (eight pieces in total) of high-performance PZT-8 series piezoelectric ceramic rings (outer diameter 55 mm, inner diameter 22 mm, thickness 6 mm) alternately stacked with pure copper electrode plates. PZT-8 material was selected due to its high Curie temperature, low dielectric loss, and excellent compressive strength to meet the stringent requirements of high-power continuous operation. The entire stack is clamped between a rear cover plate made of 45# steel and a front cover plate made of LC4 hard aluminum alloy, and axially secured by a through-center M14 high-strength prestressed bolt. During assembly, a preload of 45 N·m is applied using a precision torque wrench. This preload is designed to eliminate the tiny gaps between the ceramic plates and keep them under compression when subjected to tensile stress generated by the alternating electric field, thereby greatly improving the fatigue life and output amplitude stability of the transducer.

[0027] The minute mechanical vibrations generated by transducer 120 typically have amplitudes of only a few micrometers, insufficient for direct use in efficient cutting. Therefore, its output end is rigidly connected to a stepped acoustic amplitude transformer 130 via a precision M16x1.5 thread. The amplitude transformer's function is to mechanically amplify the input minute vibrations. In this embodiment, the amplitude transformer is precision CNC machined from TC4 titanium alloy (Ti-6Al-4V) bar stock. TC4 titanium alloy is an ideal material for manufacturing high-power amplitude transformers due to its excellent acoustic transmission characteristics (low acoustic damping), high fatigue strength, and lightweight properties. The amplitude transformer is designed as a two-stage stepped structure, with a 60 mm diameter input end connected to the transducer and a reduced 25 mm diameter output end. According to acoustic theory, its amplitude amplification factor is approximately equal to the ratio of the cross-sectional areas of the input and output ends, theoretically achieving an amplitude amplification of approximately 5.76 times. The overall length of the amplitude transformer is precisely designed to be half the wavelength of an acoustic wave, based on its operating frequency (e.g., 28 kHz), to ensure its resonant state and achieve efficient energy transfer. All its surfaces are finely polished, with a surface roughness Ra value of no more than 0.2 micrometers, to minimize energy dissipation within the material and on its surface.

[0028] The amplified vibration energy from the amplitude transformer 130 ultimately needs to be transmitted to each cutting steel wire. This crucial task is accomplished by a set of vibration transducers 140. In this embodiment, the vibration transducer 140 is not a single component, but a long, strip-shaped anvil made of cemented carbide YG8 material, with the same width as the output end face of the amplitude transformer. The lower surface of the anvil is smoothly machined and firmly bonded to the circular output end face of the amplitude transformer by vacuum brazing, forming a rigid, integral vibration structure. Its upper surface is then machined with hundreds of parallel, V-shaped micro-guide grooves according to the linear array arrangement using laser or electrical discharge machining. The dimensions of each guide groove are precisely matched to the diameter of the cutting steel wire (e.g., 0.12 mm), and the radius of the corner at the bottom of the groove is controlled at 0.07 mm to ensure that the steel wire can sit stably within it and form good contact. Once the cutting steel wire passes through these guide grooves and is subjected to working tension, the longitudinal vibration output by the amplitude transformer along its axis is efficiently converted into longitudinal contractile vibration of the steel wire along its own axis through the contact surface between the vibration transducer 140 and the steel wire. Through this meticulously designed ultrasonic vibration application assembly 100, controlled high-frequency vibration with a frequency of 28 kHz and a bidirectional amplitude of 12 micrometers can be stably excited on each cutting steel wire.

[0029] Next, refer to Figure 4This paper describes the reciprocating motion and tension coordinated control system 200 for steel wire. The system has two core tasks: first, to drive the cutting wire array to perform long-distance reciprocating linear motion at a set speed and period; second, to perform precise, real-time closed-loop control of the wire array tension throughout the dynamic process to maintain cutting stability and prevent wire breakage. Physically, the system mainly consists of a wire feeding servo motor 210 and a wire take-up servo motor 220 symmetrically arranged at both ends of the wire array, an active and passive guide wheel group 230 composed of multiple precision guide wheels, and a three-roller dynamic tension sensor 240 installed at key locations.

[0030] The wire feeding and take-up servo motors 210 and 220 are both 1.8 kW AC permanent magnet synchronous servo motors equipped with 24-bit high-resolution absolute encoders. The high-resolution encoders ensure smooth speed control and precise position response even at low speeds and frequent commutations. These two motors are connected to a dedicated motion controller 250 via their drivers through a Profinet-IRT (Synchronous Real-Time) industrial Ethernet. In this embodiment, the motion controller 250 employs a high-performance motion control card based on a field-programmable gate array (FPGA), whose hardware-level parallel processing capabilities enable it to execute complex motion and tension control algorithms with microsecond-level response times.

[0031] The guide roller assembly 230 includes an active drive roller coaxially connected to a servo motor, and multiple passive guide rollers for guiding the linear array path, increasing the wrap angle, and measuring tension. All guide rollers are made of GCr15 bearing steel, hardened and precision ground to ensure dimensional and rotational accuracy. Crucially, all guide roller surfaces in contact with the cutting steel wire have a series of V-grooves matching the linear array spacing. These grooves are coated with a 0.5 mm ± 0.05 mm thick alumina (Al2O3) ceramic coating using a plasma spraying process. This ceramic coating, after subsequent grinding and polishing, achieves a surface hardness exceeding 1300 HV and a surface roughness Ra value below 0.1 micrometers, giving the guide rollers extremely high wear resistance. This effectively prevents wear from the high-speed moving steel wire and protects the steel wire itself from damage.

[0032] Tension control is one of the key technologies for realizing this invention. A three-roller dynamic tension sensor 240 is integrated below the bearing housing of a key passive guide roller. A steel wire passes around the intermediate roller of the sensor at a specific angle, and the tension on the wire generates a vertical pressure on the intermediate roller through a lever principle. This pressure acts on a high-sensitivity strain gauge force sensor, generating a weak electrical signal proportional to the tension. After processing by the built-in amplification and filtering circuit, this signal outputs a standard analog voltage signal of 0 to 10 volts, which is acquired by a high-speed analog-to-digital converter (ADC) and sent to the motion controller 250.

[0033] The control algorithm embedded within the motion controller 250 is the soul of this system. It employs a feedforward-feedback composite control strategy. The feedback control section is a high-speed proportional-integral-derivative (PID) controller. It compares the real-time tension value fed back by the tension sensor 240 (e.g., a measured value of 30.5 Newtons) with the target value set on the human-machine interface (e.g., 30 Newtons) at a sampling and control frequency of 1 kHz. Based on the deviation between the two, the PID controller calculates a compensation torque in real time and quickly eliminates steady-state tension errors caused by factors such as load fluctuations and temperature changes by adjusting the differential torque output between the take-up motor 220 and the pay-off motor 210. The feedforward control section is mainly used to solve the problem of huge tension impact during the reciprocating motion reversal. During the system calibration phase, a dynamic model describing the linear array inertia, motor response, and friction was established through a series of experiments. This model was simplified into a look-up table and stored in the FPGA's memory. When the motion controller 250 is about to perform a reversal (i.e., decelerating from forward motion to zero and then accelerating in the reverse direction), the feedforward module calculates in advance from a lookup table, based on a preset S-shaped acceleration / deceleration curve, the additional, pulsed torque required to overcome the inertia of the entire linear array and drive system. This feedforward torque command is pre-added to the servo drive's command, and its timing precisely precedes the moment when tension fluctuates due to inertia. Through this proactive and predictive compensation, the tension overshoot at the moment of reversal can be strictly controlled within ±5% of the set value (e.g., 30 ± 1.5 Newtons), thereby completely avoiding the drastic tension fluctuations caused by frequent reversals in traditional reciprocating cutting, ensuring a smooth and efficient cutting process, and greatly reducing the risk of wire breakage.

[0034] The selection of the cutting wire is equally crucial. In this embodiment, a special carbon tool steel wire with a diameter of 0.12 mm is used, and the tensile strength of its substrate is as high as 2850 MPa. The wire surface is uniformly and firmly coated with a layer of D6 type single-crystal diamond abrasive grains with an average particle size of 6 micrometers through an advanced electroplating process. The concentration of abrasive grains in the coating and the edge projection height are strictly controlled, with the edge projection height generally maintained between one-third and one-half of the abrasive grain diameter, i.e., 2 to 3 micrometers, to ensure a sharp cutting edge while preventing premature detachment from the substrate.

[0035] Furthermore, the composite abrasive supply and circulation system 300 is described. The main function of this system is to provide a cooling lubricant containing free abrasive particles to the cutting area, enhancing the cooling effect, assisting material removal, and enabling the recycling of the cutting fluid to reduce production costs. The system includes a 100-liter storage tank 310 made of SUS316L stainless steel. A low-speed agitator at 60 rpm is installed at the bottom of the tank to continuously agitate the liquid, effectively preventing the added nano-sized abrasive particles from settling and causing uneven concentration. The side wall of the storage tank integrates a precision temperature control system based on a semiconductor cooling (TEC) module. Through closed-loop feedback control using an immersion PT100 temperature sensor, the temperature of the cutting suspension can be precisely maintained within a range of 25 degrees Celsius ± 0.5 degrees Celsius. Stable temperature means stable liquid viscosity and flowability, which is an important prerequisite for ensuring consistent cutting processes.

[0036] The cutting suspension is another key technical feature of this invention. It is not a simple coolant, but a carefully formulated composite functional liquid. Its base component is deionized water with a resistivity higher than 15 megohm-cm. Based on this, 8% by mass of nano-sized diamond powder (average particle size D50 of 50 nm) is added. These nano-abrasive particles, under the excitation of ultrasonic cavitation, can perform microscopic impact and grinding on the workpiece surface; 15% by mass of ethylene glycol is added as an antifreeze and viscosity modifier; and 1% by mass of a nonionic surfactant (e.g., polyethylene glycol octylphenyl ether) is added to improve the wettability of the suspension to silicon carbide materials and steel wires, and to help disperse the nanoparticles.

[0037] The cutting fluid suspension in the reservoir 310 is delivered via a high-precision peristaltic pump 320. A peristaltic pump was chosen because it provides a precisely adjustable, pulsation-free, and gentle delivery of the fluid without shear damage. Driven by a stepper motor, the flow rate can be linearly adjusted from 1 liter / minute to 10 liters / minute by regulating the motor speed. The fluid is then pumped to an array of nozzles 330. This nozzle array consists of multiple parallel, thin tubes made of high-hardness silicon nitride ceramic with an outlet orifice diameter of 0.8 mm. These nozzles are installed adjacent to the areas where the cutting wire enters and exits the silicon carbide ingot, continuously and uniformly spraying fresh cutting fluid at a precise angle to cover the entire array and kerf, ensuring adequate cooling, lubrication, and free abrasive supply.

[0038] Used cutting fluid, carrying a large amount of silicon carbide microparticles and detached abrasive debris, flows from below the workpiece into a multi-stage filtration and recovery device 340. This device first passes through a settling tank, where gravity causes larger particles to initially settle. The liquid then flows through a strong magnetic separator, where neodymium iron boron permanent magnets adsorb and remove any metal debris that may have been mixed in. Finally, the liquid is pumped into a high-speed centrifugal solid-liquid separator, which uses centrifugal force equivalent to 2000 times the acceleration due to gravity to efficiently separate the micron and submicron-sized silicon carbide powder suspended in the liquid. After this three-stage purification process, the liquid's cleanliness is restored, and it is then pumped back into the storage tank 310 to be mixed with fresh liquid for reuse. This not only saves a significant amount of deionized water and expensive nanodiamond abrasives but also significantly reduces wastewater discharge, aligning with the principles of green manufacturing.

[0039] Finally, the central processing and monitoring unit 400, which serves as the command center of the entire device, is described. The core hardware of this unit is a high-performance industrial-grade programmable logic controller (PLC) 410 from the Siemens S7-1500 series, paired with a 15-inch touchscreen human-machine interface (HMI) 420. The PLC 410, acting as the master station, exchanges high-speed, deterministic data with all subordinate intelligent units, including the ultrasonic generator 110, the FPGA motion controller 250, and the driver of the peristaltic pump 320, via Profinet industrial Ethernet, with a cycle time of 2 milliseconds. Operators can easily and intuitively set and modify all process parameters through the graphical HMI 420 interface, such as the frequency and power percentage of ultrasonic vibration, the linear velocity of reciprocating motion (e.g., 1.5 m / s to 2.5 m / s), the reversing cycle (e.g., 6 seconds to 12 seconds), the tension setpoint (e.g., 25 N to 35 N), and the cutting fluid flow rate. They can also monitor various status data of the equipment in real time, such as the real-time tension curve, motor speed, actual ultrasonic power, and liquid temperature.

[0040] One advanced feature of this unit is the integration of in-situ process monitoring based on acoustic emission (AE) signals. A wideband piezoelectric AE sensor 430 (frequency response range 100 kHz to 1 MHz) is securely mounted on the fixture holding the silicon carbide ingot and connected to the PLC's high-speed counting and analog input modules via a dedicated preamplifier. During the cutting process, microscopic events such as the initiation and propagation of microcracks within the material, the breakage of abrasive particles, and the formation of chips all generate high-frequency elastic stress waves, i.e., acoustic emission signals. The PLC 410 performs real-time digital signal processing on the acquired AE signals, extracting characteristic parameters such as the root mean square (RMS) value, energy, amplitude distribution, and event count rate. A normal, stable cutting process corresponds to a relatively stable AE signal baseline. Once an abnormal, large-amplitude spike pulse is detected in the signal energy or event count rate within a short period of time, this usually indicates that the cutting process has encountered hard spots, micro-defects, or localized chip blockage within the material. At this point, the PLC immediately triggers the preset "intelligent obstacle avoidance" subroutine: within 100 milliseconds, it instantly reduces the linear velocity of the reciprocating motion by 50% via bus commands, while simultaneously reducing the output power of the ultrasonic generator by 30%. This temporary, flexible handling significantly reduces stress concentration in the cutting area, helping the system smoothly navigate unstable cutting conditions. Once the PLC detects that the AE signal has returned to the normal baseline level, the system automatically and smoothly restores all parameters to their initial settings. This intelligent monitoring and proactive intervention capability based on process feedback greatly improves adaptability to complex working conditions, effectively preventing substrate breakage or wire breakage accidents caused by local overload, thereby further improving the yield and quality stability of the final product.

[0041] Example:

[0042] To verify the actual effectiveness of the method and apparatus described in this invention, a specific cutting experiment was conducted.

[0043] The experimental subject was an N-type 4H-SiC single crystal ingot with a diameter of 101.6 mm (4 inches) and a length of 25 mm. The cutting objective was to process it into a substrate wafer with a thickness of 350 μm ± 10 μm.

[0044] The cutting device used is the aforementioned specialized equipment, integrating an ultrasonic vibration application assembly, a steel wire reciprocating motion and tension coordinated control system, a composite abrasive supply and circulation system, and a central processing and monitoring unit. The cutting steel wire is 0.12 mm in diameter, with diamond abrasive grains of an average size of 6 micrometers bonded to its surface. The spacing between the wire array lines is set to 0.48 mm to account for cutting loss (Kerf Loss).

[0045] The specific process parameters are set as follows:

[0046] 1. Ultrasonic vibration parameters: The ultrasonic generator 110 is set to a working frequency of 28.5 kHz and an output power of 1200 watts. The measured axial vibration bidirectional amplitude applied to the cutting steel wire via the transducer 120, amplitude transformer 130, and vibration transducer 140 is 11.5 micrometers.

[0047] 2. Reciprocating Motion and Tension Parameters: The average linear velocity of the steel wire reciprocating motion is set to 1.8 m / s via the motion controller 250, and the commutation cycle is 8 seconds (i.e., 4 seconds for unidirectional motion). The tension setpoint is constant at 32 Newtons, and the feedforward-feedback composite control algorithm is activated, controlling the tension fluctuation during the commutation process within the range of 32 ± 1.6 Newtons.

[0048] 3. Composite abrasive supply parameters: The cutting suspension uses the aforementioned formula (8% wt. 50 nanometer diamond powder) and is supplied to the cutting area via peristaltic pump 320 at a flow rate of 6 liters / minute. The temperature control system in the storage tank 310 maintains the liquid temperature at a constant 25 ± 0.5 degrees Celsius.

[0049] 4. Feed parameters: The vertical feed speed of the worktable is set to 0.25 mm / min.

[0050] The cutting process was initiated under the aforementioned parameters, with the central processing and monitoring unit 400 monitoring the entire process. The entire cutting process was smooth, the signal baseline fed back by the acoustic emission sensor 430 was stable, and the intelligent obstacle avoidance program was not triggered.

[0051] Comparative Example

[0052] To clearly demonstrate the technical advantages of ultrasonic vibration in this invention, a comparative example is provided.

[0053] The comparative example uses the exact same cutting device, the same silicon carbide ingot, the same cutting steel wire, and the same linear array arrangement as the example.

[0054] Except for one key parameter, all other process parameters are completely consistent with the example: in the comparative example, **the ultrasonic vibration application assembly 100 is completely turned off**, that is, no axial ultrasonic vibration is applied to the cutting steel wire. The steel wire is cut only by mechanical reciprocating motion driven by the reciprocating motion and tension coordination control system 200.

[0055] The reciprocating motion and tension parameters (linear velocity 1.8 m / s, period 8 seconds, tension 32 N), composite abrasive supply parameters (flow rate 6 L / min, temperature 25 °C), and feed rate setting (0.25 mm / min) are the same as in the example.

[0056] Comparison of experimental results

[0057] After the dicing tasks in the examples and comparative cases were completed, the time consumed by the entire process, the quality of the diced substrate wafers, and the consumption of consumables were measured and statistically analyzed. Specific data comparisons are shown in the table below:

[0058]

[0059] The comparative data in the table above clearly demonstrates that the high-efficiency silicon carbide substrate cutting method based on ultrasonic vibration and radial clockwise and counterclockwise motion of steel wire proposed in this invention exhibits significant technological advancements across the board compared to traditional cutting methods that only involve reciprocating motion. After introducing axial high-frequency ultrasonic vibration, the total cutting time was drastically reduced from 265 minutes to 100 minutes, with a corresponding increase in material removal rate exceeding 165%. This fully demonstrates that the composite material removal mechanism combining "high-frequency impact chiseling" and "bidirectional sweeping grinding" greatly improves cutting efficiency.

[0060] More importantly, the significant increase in efficiency did not come at the expense of processing quality. On the contrary, the wafer surface roughness Ra value obtained in the example was only 0.18 micrometers, far superior to the 0.45 micrometers of the comparative example; at the same time, the depth of the subsurface damage layer was also significantly reduced from 4.2 micrometers to 1.5 micrometers. This indicates that ultrasonic vibration-assisted material removal is a more "gentle" and less stressful removal method, capable of obtaining higher quality processed surfaces and material integrity. In addition, the wear rate of the steel wire was reduced by more than 50%, which means that the effective service life of the dicing wire can be more than doubled, significantly reducing the consumable cost per unit output.

[0061] In summary, the specific embodiments of the present invention, through their unique device design and method, successfully couple the high-frequency ultrasonic vibration energy field with the low-frequency reciprocating mechanical field, fundamentally optimizing the processing of hard and brittle materials, and achieving a synergistic improvement in cutting efficiency, processing quality, and economic cost. It has extremely high industrial practical value and promising prospects for promotion.

Claims

1. A method for efficient cutting of silicon carbide substrates based on ultrasonic vibration and radial clockwise and counterclockwise motion of steel wires, comprising the step of driving a linear array of cutting steel wires to reciprocate and cut a silicon carbide ingot, characterized in that, The method further includes: Within a single cutting cycle, the following steps are executed in parallel and collaboratively: Activate an ultrasonic vibration application assembly (100) to generate high-frequency longitudinal vibrations of 20 kHz to 40 kHz along its own axial direction on the cut steel wire; and A tension-coordinated control system (200) drives a steel wire to reciprocate and moves it in a low-frequency reciprocating linear motion along its cutting path. The high-frequency longitudinal vibration and the low-frequency reciprocating linear motion combine to create a composite material removal mode that combines high-frequency impact chiseling and bidirectional sweeping grinding on the silicon carbide ingot, resulting in the abrasive particles fixed on the surface of the cutting steel wire acting on the silicon carbide ingot.

2. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 1, characterized in that, The step of activating the ultrasonic vibration application assembly (100) specifically includes: A high-frequency electrical signal is generated by an ultrasonic generator (110) that automatically tracks the frequency of a phase-locked loop. The high-frequency electrical signal is fed into a stacked Langevin piezoelectric ceramic transducer (120) to convert the high-frequency electrical signal into initial mechanical vibration. The initial mechanical vibration is amplified using a stepped acoustic amplitude transformer (130) rigidly connected to the transducer (120); and Through a set of vibration transducers (140) fixed to the output end of the amplitude transformer (130), the amplified mechanical vibration energy is applied to each of the cutting steel wires passing through it by contact conduction, thereby generating the high-frequency longitudinal vibration on the cutting steel wires.

3. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 2, characterized in that, The phase-locked loop frequency automatic tracking ultrasonic generator (110) can automatically track the resonant frequency point of the acoustic system including the transducer (120), the amplitude transformer (130) and the cutting steel wire, with a frequency tracking accuracy of not less than ±10 Hz. The stacked Langevin piezoelectric ceramic transducer (120) uses multiple PZT-8 series piezoelectric ceramic rings and metal electrode sheets stacked alternately and fastened by a central prestressed bolt; The stepped acoustic amplitude transformer (130) is made of TC4 titanium alloy, and its length is designed to be half the wavelength of the sound wave at its operating frequency; and The vibration transmitter (140) is made of cemented carbide YG8 material, and its upper surface has multiple V-shaped guide grooves that match the diameter of the cutting steel wire.

4. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 1, characterized in that, The steps of the drive wire reciprocating motion and tension coordinated control system (200) further include: The tension of the cutting steel wire is monitored in real time by a force sensor (240) to obtain the real-time tension value; A motion controller (250) adjusts the differential torque output of the wire feeding servo motor (210) and the wire taking servo motor (220) located at both ends of the wire array in real time through closed-loop feedback control based on the deviation between the real-time tension value and a preset tension value, so as to dynamically maintain the tension of the cutting steel wire within a narrow range near the preset tension value.

5. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 4, characterized in that, The closed-loop feedback control employs a feedforward-feedback composite tension control algorithm, wherein: The feedback control section is a proportional-integral-derivative (PID) regulator, which calculates and outputs the compensation torque based on the steady-state deviation between the real-time tension value and the preset tension value. The feedforward control section is based on a pre-calibrated system dynamics model. During the reversing phase of the cutting steel wire's reciprocating motion, it calculates the overshoot torque necessary to overcome the inertia of the linear array and drive system according to the preset acceleration and deceleration curves. This overshoot torque signal is then superimposed on the servo motor's command in advance to actively suppress tension fluctuations generated at the moment of reversal.

6. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 4, characterized in that, The reciprocating motion and tension coordinated control system (200) of the steel wire also includes a guide wheel group (230) consisting of an active drive roller and multiple passive guide rollers. All guide wheel surfaces in the guide wheel group (230) that come into contact with the cutting steel wire are provided with V-shaped guide grooves, and the surface of the guide grooves is coated with an alumina ceramic coating with a thickness of 0.5 mm by plasma spraying technology. The tension sensor (240) is a three-roller dynamic tension sensor, which calculates the real-time tension by measuring the small displacement generated by the cutting steel wire pressing its central roller.

7. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 1, characterized in that, The method further includes the step of starting a composite abrasive supply and circulation system (300), which specifically involves: A cutting suspension, formulated from deionized water, 8% by mass of nano-diamond powder, ethylene glycol, and nonionic surfactant, is continuously and uniformly supplied to the cutting area between the cutting steel wire and the silicon carbide ingot via a high-precision peristaltic pump (320) and a set of array nozzles (330). The nano-diamond powder is used as a free abrasive to assist cutting, and the cavitation effect induced by ultrasonic vibration in the cutting suspension is used to enhance cooling and chip removal of the cutting area.

8. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 7, characterized in that, The composite abrasive supply and circulation system (300) also includes a storage tank (310) with a stirrer and a temperature control module. The temperature control module maintains the temperature of the cutting suspension within a range of 25 degrees Celsius ± 1 degree Celsius through closed-loop control. The system also includes a multi-stage filtration and recovery device (340) located below the workpiece. The device consists of a settling tank, a magnetic separator, and a centrifugal solid-liquid separator. It is used to remove silicon carbide micro powder and abrasive debris from the used cutting fluid and then return the purified liquid to the storage tank (310) for recycling.

9. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 1, characterized in that, The method further includes a step of monitoring the in-situ process via a central processing and monitoring unit (400), which specifically involves: A broadband acoustic emission sensor (430) mounted on a fixture that holds the silicon carbide ingot is used to monitor in real time the acoustic emission signals generated during the cutting process due to the propagation of microcracks in the material or the formation of chips. as well as When an abnormal spike pulse indicating local hard spots or chip blockage is detected in the energy or event count rate of the acoustic emission signal, the central processing and monitoring unit (400) initiates an obstacle avoidance program, which instantly reduces the linear velocity of the low-frequency reciprocating linear motion and the amplitude of the high-frequency longitudinal vibration within 0.1 seconds. After the abnormal spike pulse disappears, the linear velocity and amplitude are restored to the normal set values.

10. The efficient cutting method for silicon carbide substrates based on ultrasonic vibration and radial clockwise / counterclockwise rotation of a steel wire according to claim 1, characterized in that, The cutting wire is a carbon tool steel wire with a diameter of 0.12 mm. Its surface is uniformly coated with a layer of single-crystal diamond abrasive grains with an average particle size of 6 micrometers through an electroplating process, and the cutting edge height of the abrasive grains is controlled at 2 to 3 micrometers. The bidirectional amplitude of the high-frequency longitudinal vibration is 5 to 15 micrometers. The average linear velocity of the low-frequency reciprocating linear motion is 1.5 m / s to 2.5 m / s, and the reversal period is 6 to 12 seconds. During the cutting process, the tension of the cutting wire is constantly controlled within the range of 25 Newtons to 35 Newtons.

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